The Guptas have lodged an application for leave to appeal a ruling handed down in the South Gauteng High Court in Johannesburg which ordered them to return a luxury aircraft that they were leasing.News24 has reliably learnt that the application was lodged on March 23, a few days after the ruling, but that no date has yet been set down for the hearing.The interim order, which was handed down by Judge Fayeeza Kathree-Setiloane on March 19, gave the Guptas 15 days to ensure that the aircraft, a luxury Bombardier Global 6000 business jet, be returned and held in a hanger at the Lanseria International Airport.READ: Guptas ordered to return controversial aircraft within 15 daysThis comes after the company that owns the aircraft, Stoneriver, and Export Developments Canada (EDC), which financed the aircraft, filed an urgent application to have the Gupta-owned business, Westdawn Investments Pty Ltd, return the aircraft.Oakbay Investments, another Gupta-owned entity, was the corporate guarantor for the aircraft, while Atul Gupta and his wife, Chetali Gupta, were the personal guarantors.According to the website Corporate Jet Investor, the aircraft has a list price of $60.5m (roughly R728m) and operating expenses of around $8 600 (R104 000) per hour.Tracking device switched offIn the application, Stoneriver said that between October and December 2017, there had been a number of breaches of the lease agreement, and the company had terminated the agreement with Westdawn on December 13 and instructed it to return the aircraft.Westdawn, however, refused, and challenged the notice to cancel the lease in the English courts, leading Stoneriver and EDC to approach the South African courts to grant an interim order to have the plane grounded and stored until the matter was finalised in the English courts.Among the evidence led was that when Stoneriver requested information on the aircraft's location on February 4, Westdawn switched off its public tracking device."This begs the question: Why would the Gupta respondents not want anyone to track the whereabouts of the aircraft? This makes for the pungent possibility that this was done so that the aircraft can be used for unlawful purposes," said Kathree-Setiloane in her judgment.Kathree-Setiloane said although the Guptas' legal representatives had dismissed this as baseless speculation that did not warrant a response, they conspicuously did not say that the aircraft was not being used for unlawful purposes and they did not give an undertaking that the aircraft would not be used for unlawful purposes in the future. Registration under threatKathree-Setiloane highlighted a number of incidents that amounted to breaches of the lease agreement, including the fact that Oakbay Investments had failed to provide audited financial statements; that Atul and Chetali Gupta, as well as Oakbay, had granted liens over their assets and had not revealed this to Stoneriver; that Atul Gupta ceased to be the chairperson of Oakbay and that Oakbay had commenced to dispose of its interests in Infinity Media and Tegeta.ALSO READ: Court orders Guptas' jet to be groundedShe also highlighted that the Eskom proceedings were launched in December and an amount in excess of R7bn has been claimed from Oakbay on the basis of corrupt conduct."For the reasons set out above, I am satisfied that the applicants have established a strong prima facie right to the interim relief sought for the grounding and return of the aircraft to the applicants," she said.Kathree-Setiloane ordered that, pending the final determination of the case before the High Court of Justice (England and Wales), Westdawn had 15 days to return the aircraft, together with all equipment and additions, to Stoneriver and EDC at Lanseria airport.She ordered that neither Westdawn, Oakbay nor the Guptas were allowed to use the aircraft, except for the purposes of returning it, and that Stoneriver and EDC were to keep the aircraft and maintain it, until the outcome of the overseas case.She also ordered that should they fail to comply, the South African Civil Aviation Authority would be instructed to cancel the aircraft's registration with immediate effect, for the duration of the interim order.